1. Field of the Invention
The present invention relates to a method and a device for measurement using laser light. In more detail, the present invention relates to a device for rotatingly irradiating two laser light beams, longitudinally symmetrical, and a method and a device for measuring an angle required for obtaining the coordinates of a predetermined point.
2. Prior Art
According to the triangular survey known in the prior art for obtaining a position on a plane, the transit was normally used. In the method using a transit, however, at least two persons were required including a surveying technician for operating the transit and an operator supporting a pole. In addition, several operators skilled in the surveying work were also needed while spending considerable operating time.
In these circumstances, the applicants of the present invention disclosed a method of surveying by using laser light in Japanese Patent Appln. No. 198,688/1985. Although this method offers an excellent survey, communications (practically wireless telecommunications) are required between a reference point and a measuring point. Thereby, survey errors were apt to occur due to error operation of the radio system, etc.
According to the principle of the invention of said application, prism and mirror, etc. are used to generate laser light in a device for rotatingly irradiating laser light. However, these means must be mounted with very high accuracies. If installation errors occur for mounting the prism and mirror, etc., the accuracies of measurement are greatly affected.
In addition, fluctuation and irregularities for rotating the laser beams should be made minimum. Consequently, the rotational irregularities in the laser device for rotatingly irradiating laser light must be made smaller, because measuring accuracies are significantly affected by irregularities, if any, in the rotation of the device for rotatingly irradiating laser light. In the above, it is known in the prior art that, the lower the rotating speed of the device for rotatingly irradiating laser light generally, the larger the said rotating irregularities become.
In addition, the prior art cannot provide a method for measuring the coordinates of a point of measurement in 3-dimensional space (3-D measurement , although a position on a plane (2-D coordinates) can be measured. Another difficulty associated with the method described above is that the range of measurement is narrow because the laser light used for the measurement based on the prior art is formed in a beam. In the measurement on a plane, no particular problems occur even if laser light is formed in beam.
In a 3-D measurement, however, inconveniency may arise during measuring work.